The present invention relates to a method and apparatus for locating the center of a structure and, more particularly, to a method and apparatus for locating the center of an opening in a vehicle for loading bulk material into the vehicle through the opening.
Dry materials, such as ash, cement, coal, or chemicals, are often transported in bulk and contained in storage compartments of a vehicle, such as a truck, train, or boat. The materials are delivered to the storage compartments through extendable loading spouts which can be moved and aligned with a hatch or opening of the vehicle through the use of drivers, such as servo motors or air cylinders or the like, which are controlled by a loading station operator.
Although these loading spouts can be moved, their range of motion is limited; therefore, the driver of the vehicle must first maneuver the vehicle into the loading area in approximate alignment with the loading spout. The driver is typically guided by the loading station operator who is located in the loading area. After the vehicle is generally aligned, the operator of the vehicle then exits the vehicle and opens the hatches of the respective storage compartments which are to be filled with the material. Once the hatch or hatches are opened, the loading station operator guides the loading spout into proper alignment with the open hatch using conventional controls. If the vehicle has several storage compartments and the loading station includes a loading spout with a long enough range of motion, and after filling the first compartment, the operator must then move and center the loading spout over the next open hatch. Otherwise the vehicle must be moved forward by the driver under the direction of the loading operator to generally align the next open hatch with the loading spout. It can be appreciated, therefore, that using these conventional techniques, the loading process is time consuming. Moreover, this process is often imprecise. Despite the presence of loading operators who can view the fill opening from their stations, the process may take several passes to properly align the spout with the opening. Even small inaccuracies or errors can result in misalignments and spillage which increase the downtime for the vehicle and, ultimately, increase the cost of the material being transported.
While recent developments have improved the maneuverability of loading spouts and their range of motion, the process of aligning the loading spout with the open hatch of the vehicle is still time consuming and also subject to human error. Furthermore, since loading stations are typically used at irregular spaced intervals during the day, an operator must be stationed at the loading station full time order to provide adequate coverage, which adds a significant cost to the goods. Consequently, there is a need for an automated loading system that will reduce the loading time and will provide a more accurate alignment of the loading spout with the opening of the vehicle and will reduce the overall operating costs.